I had to add “-church” as a negative term because there is a Foursquare Church, which is probably unrelated to social media, but it had the highest number of searches in the list below (before I excluded it).
It is worth going to Google Insights to check the interest in Foursquare over time. In 2009, most of the interest was in North America. In mid-2010, Australia and China showed interest, but Indonesia had the most interest. In early 2011, Russia showed interest. In mid 2011, Indonesia appeared to lose interest.

Google Insights does not purport to be very accurate, but these movements in search interest are interesting, particularly the rising trend line in the graph above.

I check-in most working days when I am in the city and notice that there is growing takeup by businesses offering specials. It’s still early days in Australia, but it doesn’t seem to have taken off in India and China, if the Google data is accurate.